What We Have and Haven't Learned Over Time Dept: On this day in 1957, five Air Force officers (all volunteers) and a photographer (not) stood directly underneath a Nevada Test Site nuclear detonation 18,000 feet above them - or 10,000, depending on the account - to prove how safe it was. The event was excitedly recorded by a football-game-like announcer - "It worked, it worked! A perfect, perfect shot! Just beautiful!" - followed by celebratory grins and handshakes all around as they stand by a joke placard reading "Ground Zero: Population Five." Today, most have died, though it's hard to say how many died from this. Astounding.